@u4/opencv-build


A simple script to auto build recent OpenCV + contrib version via npm. This
script is used to auto build
_opencv4nodejs_.

Main changes from the original project

- OpenCV is explicitly build with opencv-build-npm and accepting parametes see
opencv-build-npm --help
- OpenCV build can now be configured with
new OpenCVBuilder({autoBuildOpencvVersion: "3.4.16", autoBuildBuildCuda: true, autoBuildWithoutContrib: false }).install()
- Each OPENCV_VERSION will be build in his own directory.
- Each AUTOBUILD_FLAGS will be build in his own directory. (induce massive time
gain during development)
- All build can now be build outside node_modules using OPENCV_BUILD_ROOT
environement variable.
- New MSBuild.exe localisation, also works with VS 2019
- Script output is now colorized.
- Add some usefull log.
- Big code refactor.
- Enfoce typing.
- Add comments and documentations.

Each OpenCV build will take around 2Gb on your drive, so I recommand you to
define the OPENCV_BUILD_ROOT environement variable to avoid duplicate
buildsand avoid node_modules auto flushs.

Install

``bash
npm install opencv-build
`

usage

`bash
npm-opencv-build usage:
--version OpenCV version (OPENCV4NODEJS_AUTOBUILD_OPENCV_VERSION env variable)
--flags OpenCV cMake Build flags (OPENCV4NODEJS_AUTOBUILD_FLAGS env variable)
--root OpenCV-build root directory (deprecated) (INIT_CWD env variable)
--buildRoot OpenCV build directory (OPENCV_BUILD_ROOT env variable)
--cuda Enable cuda in OpenCV build (OPENCV4NODEJS_BUILD_CUDA env variable)
--cudaArch Specify the cuda arch will drasticly reduce build time, see https://en.wikipedia.org/wiki/CUDA,
ex if you have a RTX 3080 use --cudaArch=8.6, if you have also a RTX 2080 --cudaArch=7.5,8.6
(OPENCV4NODEJS_BUILD_CUDA_ARCH env variable)
--nocontrib Do not compile Contrib modules (OPENCV4NODEJS_AUTOBUILD_WITHOUT_CONTRIB env variable)
--nobuild Do build OpenCV (OPENCV4NODEJS_DISABLE_AUTOBUILD env variable)
--incDir OpenCV include directory (OPENCV_INCLUDE_DIR env variable)
--libDir OpenCV library directory (OPENCV_LIB_DIR env variable)
--binDir OpenCV bin directory (OPENCV_BIN_DIR env variable)
--keepsources Keepsources OpenCV source after build
--dry-run Display command line use to build library
--git-cache Reduce Bandwide usage, by keeping a local git souce un the buildRoot (OPENCV_GIT_CACHE env variable)
`

Requirements

- cmake

$3

for nodejs <= 12

`bash
npm install --global windows-build-tools
`

OpenCVBuildEnv options

It's possible to specify build environment variables by passing argument to the
builder script

`bash
node lib/main.js --version 4.5.5 --buildRoot ~/openCV
`

with flags, do not forget the quotes "

`bash
node lib/main.js --version 4.5.5 --buildRoot ~/openCV --flags "-DOPENCV_GENERATE_PKGCONFIG=ON -DOPENCV_PC_FILE_NAME=opencv.pc"
`

Using the bin alias

`bash
opencv-build-npm --version 4.5.5
`

Or by inserting them into the package.json where the dependency is declared an
object like:

`json
{
"opencv4nodejs": {
"autoBuildFlags": "-DOPENCV_GENERATE_PKGCONFIG=ON -DOPENCV_PC_FILE_NAME=opencv.pc",
"autoBuildOpencvVersion": "4.6.0"
}
}
`

By using environement varaibles.

`bash
export OPENCV4NODEJS_AUTOBUILD_FLAGS="-DOPENCV_GENERATE_PKGCONFIG=ON -DOPENCV_PC_FILE_NAME=opencv.pc"
export OPENCV4NODEJS_AUTOBUILD_OPENCV_VERSION="4.6.0"
export OPENCV_BUILD_ROOT="~/openCV"

node build/main.js
`

$3

The prebuild is a smart version selector, to avoid futher re-compilation,
accepted values are:

- "latestBuild" use the last built version
- "latestVersion" use the highest version number built
- "oldestBuild" use the olderst built version
- "oldestVersion" use the lowest version number built

the prebuild option intend to be use at runtime, so you do not have to keep
trak of the version you want to use.

- this parameter can only be provide in OpenCVBuildEnv constructor options.
- prebuild is ignored if OPENCV4NODEJS_DISABLE_AUTOBUILD env variable is set,
or disableAutoBuild is set in package.json

$3

Choose the openCV version you want to build, default is 4.5.5,

This option value can be provide using:

- The --version in build script
- The autoBuildOpencvVersion options field provided to OpenCVBuildEnv
constructor options.
- The autoBuildOpencvVersion field in the current package.json opencv4nodejs
object.
- The OPENCV4NODEJS_AUTOBUILD_OPENCV_VERSION environement variable.

$3

The buildRoot is the most important parameter, it define the directory used to
build openCV, Default value is the npm-opencv-build directory. You generaly want
to use this value to persist your build files out of your node_modules
directory, and buy doing som share openCV built between your project.

This option value can be provide using:

- The --buildRoot in build script
- The buildRoot options field provided to OpenCVBuildEnv constructor
options.
- The OPENCV_BUILD_ROOT environement variable.

$3

The git-cache reduce git clone data transfert, git data will be cache in you
buildRoot, so you will onlyt downdload all git file once.

This option value can be provide using:

- The --git-cache in build script
- The git-cache options field provided to OpenCVBuildEnv constructor
options.
- The OPENCV_GIT_CACHE environement variable.

$3

Set any value to enable, the following cMake flag will be added:

- DWITH_CUDA=ON
- DBUILD_opencv_cudacodec=OFF // video codec (NVCUVID) is deprecated in cuda 10,
so don't add it
- DCUDA_FAST_MATH=ON // optional
- DWITH_CUBLAS=ON // optional

This option value can be enable using:

- The --cuda in build script
- The autoBuildBuildCuda options field provided to OpenCVBuildEnv
constructor options.
- The autoBuildBuildCuda field in the current package.json opencv4nodejs
object.
- The OPENCV4NODEJS_BUILD_CUDA environement variable.

$3

Append option to CMake flags.

This option value can be enable using:

- The --flags in build script
- The autoBuildFlags options field provided to OpenCVBuildEnv constructor
options.
- The autoBuildFlags field in the current package.json opencv4nodejs object.
- The OPENCV4NODEJS_AUTOBUILD_FLAGS environement variable.

$3

Set any value to enable, this option will skip openCV Contribs.

This option value can be enable using:

- The --nocontrib in build script
- The autoBuildWithoutContrib options field provided to OpenCVBuildEnv
constructor options.
- The autoBuildWithoutContrib field in the current package.json
opencv4nodejs object.
- The OPENCV4NODEJS_AUTOBUILD_WITHOUT_CONTRIB environement variable.

$3

Set any value to disable compilation from sources.

This option value can be enable using:

- The --nobuild in build script
- The disableAutoBuild options field provided to OpenCVBuildEnv constructor
options.
- The disableAutoBuild field in the current package.json opencv4nodejs
object.
- The OPENCV4NODEJS_DISABLE_AUTOBUILD environement variable.

Generaly you should prefer using the environment variables
_OPENCV4NODEJS_DISABLE_AUTOBUILD_

$3

Over write the _OPENCV_INCLUDE_DIR_ environment variables

$3

Over write the _OPENCV_LIB_DIR_ environment variables

$3

Over write the _OPENCV_BIN_DIR_ environment variables

build test

`bash
opencv-build-npm --flags="-DBUILD_LIST=core,imgproc,imgcodecs,videoio,highgui,video,calib3d,features2d,objdetect,dnn,ml,flann,photo,stitching,gapi" --version=3.4.15 --nocontrib
`

`bash
opencv-build-npm --version=4.5.5 --nocontrib
``